The third International Workshop on Resistance to Thyroid Hormone (RTH) is planned to take place in aspen, CO on October 12-13, 1997, before the American Thyroid Association meeting in Colorado Springs, October 15-18. This arrangement would reduce the costs for the workshop as both speakers and attendees will, in most cases, be traveling to the american Thyroid Association meeting. the First International Workshop on RTH was held in 1993 in Cambridge, England and the Second in 1995 in Padua, Italy. RTH is an inherited condition caused by mutations in the thyroid hormone receptor gene and is often associated with hyperactivity and learning disabilities. To date, over 500 individuals have been identified with this condition. Study of TRH has helped understand the normal pathway of thyroid hormone action. Advances in molecular biology techniques will undoubtedly lead to the development of methods for early treatment. This Workshop is particularly planned to be accessible to young investigators who represent the future of research and to actively encourage participation by minorities and women. The RTH Workshop will include in he official program, a high proportion of successful young and minority investigators in the field and will give partial support to others in this category wishing to ABEND the Workshop. the purpose is to provide a forum for informal presentation of work in progress and lively discussion of ideas for further collaboration, rather than the traditional format of presentations by senior investigators only. To facilitate this, the Mountain Chalet family style accommodation has been selected for the base hotel for speakers and partially supported registrants at extremely low cost. Presentations and poster sessions will be held at the Given Biomedical Institute of the University of Colorado Health Science Center, Aspen; accessible from base hotel on foot or b local Aspen city bus service. Between 100-150 are anticipated.